> Why it is defvar'd here is that it no longer exists in Emacs but
> still exists in XEmacs. XEmacs people use it to run some support
> modes `fast-lock', `lazy-lock', etc. as Emacs people use
> `font-lock-support-mode'.
A note about it (not near the defvar but near the place where you force
this var to nil) would be welcome.
Stefan